1. Field of the Invention
The invention relates generally to an apparatus for raising or lowering a fryer lifting lid, such as a pressure fired fryer lifting lid. In particular, the present invention relates to a lifting lid assembly for raising or lowering a fryer lifting lid including a plurality of shafts secured to a first and second side of a lifting lid, respectively; a platform connected to each shaft; and means for raising or lowering the lifting lid connected to the platform.
2. Description of Related Art
A large capacity pressure cooker or pressure fired deep fat fryer generally includes a vat or cooking vessel of a sufficient size to receive a wire basket or tray carrier, in which the food product to be cooked is held. A suitable tray carrier may be configured to receive a plurality of food product trays. Such tray carriers are disclosed in U.S. Pat. No. 6,085,640, the disclosure of which is incorporated herein by reference. The basket or tray carrier is thereafter submersed in a cooking medium, such as melted shortening or cooking oil, which is contained in the vat or the cooking vessel. The cooking vessel may be closed by a lid, which makes a seal with an upper edge of the cooking vessel. The seal may maintain pressure within the vat or cooking vessel and prevent spillage and splashing of a cooking medium.
Alternatively, a large capacity cooker may be of an open-well design, as described in U.S. Pat. No. 5,402,712, the disclosure of which is incorporated herein by reference. In such cookers, the lid of the cooker is an open frame permitting direct access to the cooking vessel and to the food products submersed therein. The frame may support a wire basket for holding food products or a food tray carrier for carrying a plurality of trays containing food products. Although the frame does not form an air-tight seal with the upper edge of the cooking vessel, the frame also may reduce spillage and splashing of the cooking medium from the cooking vessel during cooking.
Referring to FIG. 1, in one known configuration, the lid lifting assembly includes a support frame 100 vertically oriented and secured to a rearward end of the pressure cooker. Support frame 100 includes a pair of vertical guide rails 102 and 104, each having a U-shaped cross-section and opening toward each other. Guide rails 102 and 104 are joined together at their upper and lower ends by top and bottom horizontal frame members 106 and 108. The front, rear, sides, and top of the support frame may be enclosed by panels, eg., stainless steel panels forming a lid lifting device housing, which forms a portion of a cooker cabinet or a cooker transfer cart. A frame-like carriage 120 is mounted vertically within support frame 100. Carriage 120 has rollers 122a-b and 124a-b which are adapted to be received within support frame guide rails 102 and 104, respectively. Consequently, carriage 120 may be positioned vertically within support frame 100. A pair of horizontal arms 126 and 128 may be affixed to carriage 120. Each of arms 126 and 128 extend from carriage 120 toward the cooker lid through a vertical slot (not shown) in the panel covering the front of support frame 100 or between the front and side panels. The cooking vessel lid of the fryer is mounted on horizontal arms 126 and 128.
A cable drum 130 may be driven by an electric motor 132 mounted on top horizontal frame member 106. In a further known configuration, a pair of cables 134 and 136 are provided, each cable having one end attached to drum 130 and the other end attached to carriage 120. One of the cables may be slightly longer than the other and, consequently, the longer cable does not bear the weight of carriage 120. The longer cable serves as a back-up cable if the primary cable fails. Drum 130 is rotatable in a first direction by electric motor 132 to raise carriage 120 within support frame 100 and consequently raising arms 126 and 128 and the lid therewith. Drum 130 is rotatable in the opposite direction by electric motor 132 to lower carriage 120 within support frame 100 and to lower arms 126 and 128 and the lid therewith. In this manner, the lid of the pressure cooker is shifted between its lowered position seated upon the upper edge of the cooking vessel and its raised position.
In yet another known configuration, the cooker lid may be pivotally mounted to a support brace for pivotally mounting the cooker lid on a monorail lifting device, and the lid also may be manually raised and lowered with the assistance of a counterbalance weight supported in the lid lifting device housing, as described in U.S. Pat. No. 5,974,955, the disclosure of which is incorporated herein by reference.
In a closed lid cooker or a pressure fired fryer, the food product is cooked for the desired length of time under both elevated heat and pressure. Following the cooking cycle, an operator may relieve the pressure in the vat or cooking vessel and then may open the lid in order to remove the wire basket or fryer tray carrier or may simply remove the food product from the wire basket or fryer tray carrier.
Regardless whether an open or closed lid fryer is used, the lid may include a wire basket or a tray carrier loaded with trays and food product covered with residual cooking medium and may be heavy and may be difficult to raise and lower. Further, because the lid must be of sufficiently heavy construction to properly withstand the pressure within the cooking vessel during the cooking cycle, it may be difficult for some operators to lift the lid to load or unload the cooker, or remove the wire basket or fryer tray carrier. To overcome this problem, operators have employed various types of automatic apparatus for opening and closing the cooker lid. In some instances, these various apparatus are used to additionally hold the lid down and in a sealed position during the pressurized operation of the cooker.
Some known lid raising and lowering apparatus require powerful power train means. The positioning of the lid lifting apparatus behind the vat or cooking vessel makes maintenance and repair awkward. Further, lid lifting creates additional torque on the lid lifting apparatus when raising or lowering a full or partially full wire basket or tray carrier. Electro-mechanical or hydraulic systems have been used for opening and closing the lid, but these systems have experienced significant maintenance problems and resultant down-time. In addition, some of the raising and lowering means are sufficiently complex to require a skilled operator. As a result, efforts to mechanize the operation of large capacity pressure cookers by means of electro-mechanical or hydraulic controls for raising and lowering the lids of the cooking vessels have on occasion produced more problems than they have solved. In addition, the more complex and the more exposed the raising and lowering apparatus, the more susceptible the apparatus is to the adverse effects due to contamination of operating components with dust, dirt, and cooking medium residue.
Thus, a need has arisen for a lifting lid assembly that is sufficiently strong to support a lifting lid during a covering and uncovering of a cooking vessel, but which also may be compact and of light weight.
A further need has arisen for a lid lifting apparatus that avoids excess torque when raising or lowering a fall or partially full wire basket or tray carrier. It is an advantage of the present invention that it utilizes the mechanically advantageous positioning of the lifting shafts at or near the center of gravity of the lifting lid.
Still a further need has arisen for a lid lifting apparatus the components of which are positioned at opposite sides of the vat or cooking vessel. It is a feature of this design that the shafts, shaft/lid connections, and lifting apparatus are readily accessible from the sides or front of the fryer. It is an advantage of this positioning of the lifting apparatus that it may be more readily maintained and repaired without the need to obtain access to the rear of the fryer or to work over the vat or cooking vessel or over or under the lifting lid.
According to an embodiment, the present invention is a lifting lid assembly for raising and lowering a lifting a lifting lid of a cooking vessel. The lifting lid assembly comprises a lifting lid and a first shaft and a second shaft. The shafts are positioned on a first side and a second side of the lifting lid, respectively, where the first side is opposite the second side, each shaft supports the lifting lid, and an upper portion of the shaft may be secured to the lifting lid. The lifting lid assembly farther comprises a first platform and a second platform, which platforms are secured to a lower portion of the first shaft and the second shaft, respectively, and a first pair and a second pair of spring motor cables. At least one of the first pair and the second pair of cables is connected to the first and the second platforms, respectively. The lifting lid assembly also comprises a first pair and a second pair of spring motors. Each of the first pair and the second pair of spring motors is connected to the first platform and the second platform, respectively, by at least one of the first pair and the second pair of spring motor cables, respectively.
The spring motor cables also may be wound to raise the lifting lid. Moreover, the first shaft and the second shaft also may be positioned below the lifting lid, and the upper portion of each shaft may be substantially flush with an upper edge portion of the lifting lid.
In another embodiment, the present invention is a lifting lid assembly for raising and lowering a lifting lid of a cooking vessel. The lifting lid assembly comprises a lifting lid and a first shaft and a second shaft. The shafts are positioned on a first side and a second side of the lifting lid, respectively, where the first side is opposite the second side, each shaft supports the lifting lid, and an upper portion of each shaft may be secured to the lifting lid. The lifting lid assembly further comprises a first platform and a second platform, which platforms are secured to a lower portion of the first shaft and the second shaft, respectively, and a first spring cable and a second spring cable. The first cable and the second cable are connected to the first platform and the second platform, respectively. The lifting lid assembly also comprises spring means, which are adapted to assist in a raising and lowering of the lifting lid. The spring means are connected to the first platform by the first spring cable, and to the second platform by the second spring cable. Further, in this embodiment, the first spring cable and the second spring cable are wound to raise the lifting lid, the first shaft and the second shaft are positioned below the lifting lid, and the upper portion of each shaft is substantially flush with an upper edge portion of the lifting lid.
The lifting lid assembly further may comprise a first counterbalance weight and a second counterbalance weight connected to the first platform and the second platform, respectively, by a first counterbalance cable and a second counterbalance cable threaded through a first pulley and a second pulley, respectively. Each of the counterbalance weights may be positioned at a rearward side of the fryer, and may be adapted to assist the spring means in raising and lowering the lifting lid.
In still another embodiment, the present invention is a lifting lid assembly for raising and lowering a lifting lid of a cooking vessel. The lifting lid assembly comprises a lifting lid and a first shaft and a second shaft. The shafts are positioned on a first side and a second side of the lifting lid, respectively. The first side is opposite the second side, each shaft supports the lifting lid, and an upper portion of each shaft may be secured to the lifting lid. The lifting lid assembly further comprises a first platform and a second platform, which platforms are secured to a lower portion of the first shaft and the second shaft, respectively, and a first cable and a second cable connected to the first platform and the second platform, respectively. The lifting lid assembly also comprises means for raising and lowering the lifting lid. The means for raising and lowering the lifting lid is connected to the first platform by the first cable, and to the second platform by the second cable.
The first shaft and the second shaft may be positioned below the lifting lid, and the upper portion of each shaft may be substantially flush with an upper edge portion of the lifting lid. Moreover, the means for raising and lowering the lifting lid may comprise a first spring connected to the first platform by the first cable, and a second spring connected to the second platform by the second cable. The first cable and the second cable may be wound to raise the lifting lid. Further, the means for raising and lowering the lifting lid may comprise a first age counterbalance weight and a second counterbalance weight connected to the first platform and the second platform, respectively, by a first counterbalance cable and a second counterbalance cable threaded through a first pulley and a second pulley, respectively. Each of the counterbalance weights may be positioned at rear side of the fryer, and may be adapted to assist the spring means in raising and lowering the lifting lid.
Other objects, features, and advantages will be apparent to persons of ordinary skill in the art in view of the following detailed description of the invention and the accompanying drawings.